Blood clots in the brain..I just dont understand?

You should convince/"force" him to see a Dr with you, if you are very close to him and he agrees. My thought is that his blood clot may have resolved, or largely resolved. But his problem now is his headache. You can get nose bleed in severe headache, when the intracranial pressure is high, or even when he dig his nose too much. A CT scan of his head can tell how large is the blood clot now, and whether it is affecting certain part of the brain, or related to the nose bleed.